A through-arm robotic MIG welding torch system generally includes a multi-axis robotic arm and a welding torch mounted to a distal end of the robotic arm. A power cable connects the welding torch to a source of welding power, consumable electrode wire, shielding gas, and optionally cooling liquid. The power cable may be a unicable design in which welding power, electrode wire, shielding gas, and optionally cooling liquid are all transferred within a single cable assembly from the source to the welding torch. The power cable extends from the source and internally through the robotic arm to the welding torch.
In all through-arm robotic MIG welding torch systems, the power cable has a fixed length. Also, as shown in FIG. 1, conventionally the wire feeder 10 connected to the power cable 12 is fixedly mounted on the robotic arm 14 such that the wire feeder is stationary relative to the robotic arm. As the robotic arm 14 moves in a robotic path shown by two-headed arrow 16 (for instance, the robotic arm may rotate about its 5th axis from at least a +120 degree disposition to at least a −120 degree disposition), the power cable 12 binds/compresses because it cannot extend or contract in length due to the fixed position of both ends of the power cable (fixed point 18, fixed point 20). This causes unwanted stress in the power cable 12 as well as the wire, liner, and other components located internally in the cable. If the power cable becomes bound within the robotic arm, a harsh “snapping” transition occurs when the robotic arm articulates back to its original disposition. This “snapping” transition also results in increased wear and stress on the system, all of which can lead to premature power cable failure and undesirable downtime.